2-Distribution of Scores

Question 1

What is a distribution?

Answer 1

The relative frequency with which values of a variable occur in a sample or population.

Question 2

What is a frequency table?

Answer 2

It conveys the number of scores in a sample or population having each value of a variable.

Question 3

What is Raw frequency counts (tallies)?

Answer 3

It represent the number of scores in a sample or population having a particular value or falling in a given interval. (f)

Question 4

What are relative frequencies?

Answer 4

It represent the proportion (p) of scores in a sample or population having a particular value or falling in a given interval.

(frequency of one value divided by the total of frequency)

Question 5

What is cumulative frequency?

Answer 5

The number of scores at or below a given value of a variable.

Question 6

What are cumulative proportion?

Answer 6

The proportion of scores at or below a given value of a variable.

Question 7

What is a percentile rank?

Answer 7

cumulative proportionx100= %

Question 8

What is the difference between a histogram and a bar graph?

Answer 8

Histograms have :

1) A natural ordering on the x-axis
2) No space between the bars

Question 9

What is an interval?

Answer 9

A range of values of a quantitative variable.

Question 10

How do you calculate the range of scores?

Answer 10

Max-min

Question 11

Interval width depends on what ?

Answer 11

1) The number of intervals we wish to have

2) The range of scores in the data set

Question 12

What are score limits of an interval?

Answer 12

the minimum and maximum whole values (expressed by whole numbers) of the units of measurement that define the interval.

Question 13

What are real limits?

Answer 13

the minimum and maximum real values of scores that define the interval.

Question 14

How do you calculate relative frequency?

Answer 14

The same way you calculate proportion (f/n=proportion or relative frequency)

Question 15

What is subjective probability?

Answer 15

An individual’s subjective judgment about the likelihood that some event will occur.

Question 16

What are objective probabilities?

Answer 16

Numerical expressions of the likelihood of some event occurring.

Question 17

What is the outcome of a sampling experiment?

Answer 17

is the value of the variable that was selected.

Question 18

What is a sampling experiment ?

Answer 18

the random selection of one of the possible values of a variable.

Question 19

What is the proportion of success?

Answer 19

is the number of successes divided by the number of sampling experiments,

p = Nsuccess/NSE.

Question 20

What is an event?

Answer 20

one or more of the possible outcomes of a sampling experiment.

is p = (Nsuccess+Nsuccess)/NSE

Question 21

What defines the probability of an event?

Answer 21

is the proportion of times the event would occur if the same sampling experiment were repeated INFINITETLY many times.

Question 22

In probability, what is mutual exclusivity?

Answer 22

Two events that cannot co-occur.

Question 23

In probability, what is independance?

Answer 23

the occurrence of one event does not affect the probability of the other occurring.

Question 24

What is probability distribution?

Answer 24

The probability that a randomly selected score will have a given value or fall in a given interval. In other words, shows the proportion of scores falling in any interval.

Question 25

How does p(A) reads?

Answer 25

probability of ‘‘A’’

Question 26

In p(An) , what does n stands for?

Answer 26

n= any interger

Question 27

What are the features of probability distributions?

Answer 27

1) Probability of any event A, is between 0 and 1.

2) The sum of all probability (A1+A2…+An) = 1

Question 28

What is a probability density function?

Answer 28

It plots the density of scores at each value of a continuous variable.

Question 29

How do we calculate density?

Answer 29

density= proportion of scores in an interval / interval width

d=p/w